Polycarbonates are well known as tough, clear, highly impact resistant thermoplastic resins. Polycarbonates, however, possess relatively high melt viscosity. The polycarbonate of 4,4'-isopropylidenediphenol (bishpenol A polycarbonate), for instance, is a well know engineering molding plastic.
In order to prepare a molded article from polycarbonate, relatively high extrusion and molding temperatures are required. In order to reduce the melt viscosity while also maintaining the desired physical properties, methods including the addition of plasticizers, the incorporation of aliphatic chainstoppers, the reduction of molecular weight, and the preparation of blends of polycarbonate with other polymers have been practiced.
U.S. Pat. No. 5,510,448 discloses a copolyestercarbonate composition derived from a dihydric phenol, a carbonate precursor, and an aliphatic alpha omega dicarboxylic acid or ester precursor.
U.S. Pat. No. 5,025,081 discloses a process of preparing a coplyestercarbonate in which an aliphatic alpha omega diacid is incorporated into aromatic polycarbonate backbones. The process involved a method in which the pH is adjusted in a stepwise manner.
U.S. Pat. No. 4,983,706 discloses a process for preparing a polyestercarbonate which comprises reacting interfacially a dihydric phenol, a carbonate precursor, and the salt of an aliphatic alpha omega dicarboxylic acid having from 8 to about 20 carbon atoms.
Known methods for incorporating diacid residues into polycarbonate involve the incorporation of at least one alpha, omega diacid residue.